Index Archive

11 November 2015

MI5 is responsible for countering threats to British national security, including terrorism, espionage, cyber threats and the proliferation of weapons of mass destruction.

MI5 is led by Director General Andrew Parker. Organization employs around 4,000 staff members who are organized into nine branches, each with specific areas of responsibility.

Established in 1909 as the Secret Service Bureau, MI5 and MI6 soon grew from modest beginnings to become professional and effective intelligence agencies. MI5, founded by Captain (later Major General) Vernon Kell, played a central role in the capture of most of Imperial Germany's intelligence agents in the UK at the start of World War I.

The Security Service has had a variety of names, most famously MI5, since it was established in 1909. This has often led to confusion about what the Service has been called at various points in its history.

October 1909 -

The Security Service is founded as the Home Section of the Secret Service Bureau, under Captain Vernon Kell. It is placed under the nominal supervision of the Directorate of Military Operations of the War Office, the predecessor of today's Ministry of Defense.

The branch of the DMO responsible for the Secret Service Bureau is called MO5.

April 1914 -

The Secret Service Bureau is absorbed into the War Office for the duration of the war. It becomes part of section 5 of the Directorate of Military Operations and is given the name MO5(g).

September 1916 -

MO5(g) is moved across to the newly established Directorate of Military Intelligence within the War Office. It becomes section 5 of the Directorate of Military Intelligence - hence MI5.

1929 -MI5 is renamed as the Defense Security Service.

1931 -The Defense Security Service becomes the Security Service, the name by which it is still known today. However, "MI5" is still widely used as a short alternative to our official name.

The establishment of the Secret Service Bureau –

The Security Service (MI5) and the Secret Intelligence Service (SIS or MI6) began operations in October 1909 as a single organization, the Secret Service Bureau, staffed initially by only two officers: the fifty-year-old Royal Navy Commander Mansfield Cumming and an Army captain fourteen years his junior, Vernon Kell.

Cumming and Kell later parted company to become the first heads of, respectively, the future SIS and MI5.

As well as being an accomplished linguist, Kell also proved adept at running an office on a shoestring. At the outbreak of war in August 1914, he had only sixteen staff (including the caretaker), well below the minimum which any modern security service would think necessary in order to function at all.

Kell’s original remit was to deal with what an official committee reported in 1909 was ‘an extensive system of German espionage’, based largely on German nationals in Britain. ‘Refuse to be served by a German waiter’, the Daily Mail advised its readers.

‘If your waiter says he is Swiss, ask to see his passport.’ Such alarmism reflected the tensions caused by the Anglo-German naval arms race and the approach of the First World War.

Most of the ‘spies’ who persuaded Whitehall that it was faced with ‘an extensive system of German espionage’ in Britain were figments of the media and popular imaginations.

After initially pursuing some false leads, Kell discovered a real network of spies working for German Naval Intelligence who, because of the naval arms race, presented a significant threat to British security.

As Home Secretary in 1910-11, Winston Churchill, the greatest intelligence enthusiast in all the cabinets in which he served, enabled Kell to make maximum use of his slender resources in two vital ways.

Secondly, Churchill introduced a system of Home Office Warrants (HOWs), each personally authorized by the Home Secretary, which authorized the interception of all the correspondence of suspects. Hitherto individual warrants signed by the Home Secretary had been required for every letter opened. Home Office Warrants are still used today and the Home Secretary continues to be responsible for authorizing them. These new arrangements proved crucial in enabling MI5 to investigate suspects.

At the start of the First World War, with the assistance of the police, MI5 rounded up all the agents of any significance working for German naval intelligence.

No remaining agent was able to pass on potentially crucial intelligence on the departure for the continent of the British Expeditionary Force.

Gustav Steinhauer, the head of the British section of German Naval Intelligence, later acknowledged that the Kaiser had been beside himself with fury when told of the ‘wholesale round-up of our secret service agents’: ‘Apparently unable to believe his ears, [he] raved and stormed for the better part of two hours about the incompetence of his so-called intelligence officers, bellowing: “Am I surrounded by dolts? Why was I not told? Who is responsible?” and more in the same vein.’ Steinhauer is unlikely to have fabricated such a devastating denunciation of his own alleged incompetence.

German archives reveal that at least 120 spies were sent to Britain at some point during the First World War. MI5 caught 65 of them. There is no convincing evidence that any of the remainder sent back significant intelligence to Germany. Some appear to have been ‘reconnaissance agents’ on neutral shipping, able to report only on what they could observe when calling at British ports. A number of other agents broke contact with their case officers.

A post-war MI5 report concluded: ‘It is apparently a paradox, but it is none the less true, and a most important truth, that the efficiency of a counter espionage service is not to be measured chiefly by the number of spies caught by it.’

Though MI5 caught a record number of spies in 1915, it was probably less successful then than in 1918 when it caught none. Good ‘protective security’ (better developed during the First World War than ever before) and the deterrent effect of the executions of some captured spies had by then made it difficult for Germany either to recruit any spies for work in Britain or to carry out sabotage operations as effective as those in the United States (which included blowing up a huge arms dump in New Jersey in which 900 tonnes of explosives was detonated, killing seven people and damaging the Statue of Liberty).

Faced with the declining threat from German espionage, MI5 paid increasing attention during the second half of the War to counter-subversion.

Like the government, it wrongly suspected that German and Communist subversion was inflaming British industrial disputes. Its New Year Card for 1918, correctly forecasting victory by the end of the year, showed MI5, depicted as a masked Britannia, impaling the beast of Subversion with her trident before it can stab the British fighting man in the back. The card was personally designed by Kell’s long-serving deputy, Eric Holt-Wilson.

In the course of the war MI5’s staff increased almost fiftyfold to reach a total of 844. Though the leadership remained overwhelmingly male, several female recruits achieved positions of greater significance than in any other British official agency or department.

Miss A. W. Masterson became the first woman to manage the finances of a government office.

Jane Sissmore, who joined MI5 as a sixteen-year-old secretary straight from school in 1916, progressed so rapidly that by 1924 she had qualified as a barrister and become MI5’s chief expert on Soviet affairs.

Though the intelligence glass ceiling was not broken until Stella Rimington became Director General of MI5 in 1992, the first cracks began to appear in the First World War.